Antiapoptotic activity of autocrine interleukin-22 and therapeutic effects of interleukin-22-small interfering RNA on human lung cancer xenografts.
OBJECTIVE
Non-small cell lung carcinoma (NSCLC) is one of most common malignant diseases and usually is resistant against apoptosis-inducing chemotherapy. This study is to explore the antiapoptotic mechanisms of interleukin (IL)-22 in human lung cancer.


METHODS
Nineteen cases with stage I to III NSCLC were collected to determine the expression of IL-22. Stable transfection of human IL-22 cDNA into A549 and PG cells and transfection of IL-22-RNA interference (RNAi) into these cancer cell lines were done to reveal the molecular mechanisms of IL-22.


RESULTS
It was found that IL-22 was highly expressed in primary tumor tissue, malignant pleural effusion, and serum of patients with NSCLC. IL-22R1 mRNA was also detected in lung cancer tissues as well as lung cancer cell lines. Overexpression of IL-22 protected lung cancer cell lines from serum starvation-induced and chemotherapeutic drug-induced apoptosis via activation of STAT3 and its downstream antiapoptotic proteins such as Bcl-2 and Bcl-xL and inactivation of extracellular signal-regulated kinase 1/2. Exposure to blocking antibodies against IL-22R1 or transfection with the IL-22-RNAi plasmid in vitro resulted in apoptosis of these lung cancer cells via STAT3 and extracellular signal-regulated kinase 1/2 pathways. Furthermore, an in vivo xenograft study showed that administration of IL-22-RNAi plasmids significantly inhibited the human tumor cell growth in BALB/c nude mice.


CONCLUSIONS
Our study indicates that autocrine production of IL-22 contributes to human lung cancer cell survival and resistance to chemotherapy through the up-regulation of antiapoptotic proteins.
Zhang
Weici
W
Institute of Immunology, University of Science and Technology of China, Hefei, People's Republic of China.
Chen
Yongyan
Y
Wei
Haiming
H
Zheng
Chaogu
C
Sun
Rui
R
Zhang
Jian
J
Tian
Zhigang
Z
D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology / Q000628:therapy; D016022:Case-Control Studies; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation; D006801:Humans; D007124:Immunoenzyme Techniques; D007378:Interleukins / Q000235:genetics*; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016066:Pleural Effusion, Malignant / Q000235:genetics / Q000473:pathology / Q000628:therapy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000627:therapeutic use*; D018123:Receptors, Interleukin / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D000097043:Interleukin-22
D020169:Caspases; D007378:Interleukins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018123:Receptors, Interleukin; D050796:STAT3 Transcription Factor; D000097043:Interleukin-22; C415369:interleukin-22 receptor